The central neurochemistry service has continued a high level of activity in analytical methods development and analysis of human fluids and tissues. Routine analysis is presently available for EM, HVA, 5HIAA, 5-HT, NE and normetanephrine in plasma. These compounds as well as VMA, DOPAC, epinephrine, dopamine, metanephrine, and 3-methoxytyramine can be measured in urine. In addition, CSF measures of epinephrine, NE, DA, HVA, 5HIAA, MHPG, free and conjugated metanephrine and normetanephrine, and 5-HT are possible. A new GC-MS assay for metanephrine and nonnetanephrine, the 0-methylated metabolites of epinephrine and norepinephrine, respectively, has been applied. Conjugated and free forms of these compounds are now determined in CSF, allowing for greatly improved clinical studies on the action of MAOIs in humans. Analysis for MCPP, a serotonin agonist, has been incorporated into the repertoire of central laboratory analyses.